We are given an Excel document that has a Crackme. When we try to test a key, a cheeky popup appears, tells us we are wrong, closes Excel, and launches calc.exe.
When we open the document back up and look at the macros there is only one very simple macro to close the document, so there are definitely some shenanigans.
Sub excelulate() Application.Quit End Sub
If we right click on the sheets on the bottom and click unhide there is a secret hidden sheet.
If we go to the secret sheet, click “Show Formulas” and make the font black then we can see there are Excel functions in the cells. There is one cell that looks interesting at A14 that is referring to a super secret sheet that we cannot see.
I modified the macro to try and make all of the sheets visible and clicked the button.
Sub excelulate() Dim x As Worksheet For Each x In Sheets x.Visible = True Next End Sub
We can now see a super secret sheet with more formulas. It is pretty amazing that there can be hidden and then super hidden sheets in Excel.
If we remove uncheck “Show Formulas” and remove everything from F13 besides the concatenate function, Excel will print the formula for us.
If we enter that key into the original file we get the winning message and find that we are the EXCELULATOR! It is pretty amazing all the things you can do with Excel.